Despite the aviation giant’s assurances that the plane is safe and reliable, the European Union, Britain, India and China joined other countries in grounding the plane or banning it from their airspace as they await the results of the investigation into the crash.

However, the US has so far refused to take similar action against the US aerospace giant’s best-selling workhorse aircraft.

“Thus far, our review shows no systemic performance issues and provides no basis to order grounding the aircraft,” Federal Aviation Administration (FAA) chief, Daniel Elwell, said in a statement on Tuesday.

A new Ethiopian Airlines 737 MAX 8 went down minutes into a flight from Addis Ababa to Nairobi on Sunday, killing all 157 people on board.

The widening actions against the aircraft put pressure on Boeing, the world’s largest aeroplane manufacturer, to prove the MAX planes are safe, and the company has said it is rolling out flight software updates by April that could address issues with a faulty sensor.

The full extent of the impact of these aircraft bans on international travel routes was unclear. There are about 350 MAX 8 planes currently in service around the world, according to the AFP news agency.

Air Canada, for example, announced it was cancelling some of its flights to London following Britain’s decision to ban the aircraft. The EU aviation safety agency also closed European airspace to all MAX planes.

Trump tweets

US President Donald Trump weighed in with a blistering tweet on Tuesday: “Airplanes are becoming far too complex to fly.”

“Pilots are no longer needed, but rather computer scientists from MIT,” he wrote, referring to the prestigious university.

Trump later spoke by telephone to Boeing CEO Dennis Muilenburg, who assured him the aircraft is safe, an industry source told AFP.

US carriers have so far appeared to maintain confidence in Boeing, which has been ordered by the FAA to make changes to flight systems and pilot training procedures.

Boeing has described the MAX series as its fastest-selling family of planes, with more than 5,000 orders placed to date from about 100 customers.

But not since the 1970s, when the McDonnell Douglas DC-10 suffered successive fatal incidents, has a new model been involved in two deadly accidents in such a short period.

The plane involved in Sunday’s crash was less than four months old, with Ethiopian Airlines saying it was delivered on November 15.

It went down near the village of Tulu Fara, about 60km east of Addis Ababa.

Ethiopian Airlines chief executive Tewolde GebreMariam said the plane had flown in from Johannesburg, spent three hours in Addis and was “dispatched with no remark,” meaning no problems were flagged.

Investigators have recovered the black box flight recorders, which could potentially provide information about what happened, depending on their condition.